For this situation the signalling never claims to be. It has always been the expectation that the driver possesses and correctly applies the relevant route knowledge.
Again, a scenario TPWS wasn’t conceived to cover. In theory it would be possible to install an overspeed grid somewhere, but there would be an element of challenge to design it in order to be able to be effective against an accelerating train, which is what we believe to be the scenario here.
Continuous ATP with supervision of braking curves is the gold-plated solution, but we’re a very long way away from this network-wide. As stated elsewhere, by coincidence this particular location looks likely to get it fairly soon.
It’s certainly the sort of thing which should be covered as part of the competence management process. Signing a location is normally a declaration of being able to drive over all of the layout, so that certainly includes routes not routinely covered. We’re jumping the gun a bit though, as we don’t know whether this was a missed junction indicator, misremembering the speed limit, lapse of concentration, or whatever.